What is the appropriate workup and management for a suspicious nodular thickening of the left adrenal gland?

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Last updated: March 10, 2026 • View editorial policy

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Workup and Management of Suspicious Nodular Thickening of the Left Adrenal Gland

All patients with a suspicious adrenal nodular thickening require both comprehensive hormonal screening and radiologic characterization to exclude life-threatening conditions including pheochromocytoma, adrenocortical carcinoma, and functioning adenomas. 1

Initial Imaging Characterization

Obtain a non-contrast CT scan as first-line imaging to measure Hounsfield units (HU) and distinguish benign from suspicious lesions 1:

  • HU ≤10: Diagnostic of benign lipid-rich adenoma—no further imaging needed regardless of size 2
  • HU >10: Requires second-line imaging with either:
    • Contrast washout CT, OR
    • Chemical shift MRI 1

Critical caveat: Approximately 1/3 of pheochromocytomas can mimic benign adenomas on washout CT, and 1/3 of true adenomas may not washout appropriately. Even malignant masses can show adenoma-range washout 1. Chemical shift MRI is equally acceptable and avoids radiation.

Mandatory Hormonal Evaluation

Screen ALL patients regardless of symptoms 1:

1. Autonomous Cortisol Secretion (Universal Screening)

  • 1 mg overnight dexamethasone suppression test (preferred method) 1
  • Cortisol >50 nmol/L (>1.8 µg/dL) post-dexamethasone indicates mild autonomous cortisol secretion (MACS)
  • This matters because MACS increases cardiovascular morbidity and mortality even without overt Cushing's syndrome 2

2. Pheochromocytoma Screening

  • If HU >10 OR any signs/symptoms of catecholamine excess: Measure plasma or 24-hour urinary metanephrines 1
  • If HU <10 AND no symptoms: Screening not required 1
  • Critical: Must exclude pheochromocytoma before any biopsy to prevent hypertensive crisis 1

3. Primary Aldosteronism

  • Only if hypertension and/or hypokalemia present: Check aldosterone-to-renin ratio 1

4. Adrenocortical Carcinoma Markers

  • If imaging suspicious for malignancy OR virilization signs: Check serum androgens (DHEA-S, testosterone) 1

Size-Based Risk Stratification

Lesions >4 cm that are inhomogeneous or HU >20 have sufficiently high malignancy risk that surgery is usually indicated 2:

  • <4 cm + benign imaging (HU <10): No follow-up needed if non-functional 1
  • ≥4 cm + benign imaging (HU <10) but non-functional: Repeat imaging at 6-12 months 1
  • >4 cm + indeterminate imaging: Multidisciplinary discussion required 1

Surgical Indications

Proceed with adrenalectomy for 1:

  1. Functional masses:

    • Clinically apparent Cushing's syndrome
    • Pheochromocytoma (always)
    • Aldosterone-secreting adenoma (after adrenal vein sampling confirmation)
    • MACS with progressive metabolic comorbidities in younger patients (shared decision-making)

  2. Suspected malignancy:

    • Lesions >4 cm with HU >20 or inhomogeneous appearance
    • Growth >5 mm/year on follow-up (repeat hormonal workup first) 1

  3. Surgical approach:

    • Minimally invasive surgery preferred for most cases 1
    • Open adrenalectomy for suspected adrenocortical carcinoma >6 cm or locally advanced disease 1

Role of Biopsy

Do NOT perform routine biopsy 1. Only consider if:

  • Suspected metastasis from known extra-adrenal malignancy
  • Pheochromocytoma definitively excluded first
  • Never biopsy suspected adrenocortical carcinoma (risk of tumor seeding)

Follow-Up for Non-Operative Management

For indeterminate non-functional lesions 1:

  • Repeat imaging at 3-6 months with shared decision-making about surgery
  • If growth <3 mm/year: No further follow-up needed
  • If growth >5 mm/year: Consider surgery after repeat hormonal workup

Multidisciplinary Review Triggers

Obtain endocrinology, surgery, and radiology consultation when 1:

  • Imaging not consistent with benign lesion
  • Any hormone hypersecretion detected
  • Significant growth on follow-up
  • Surgery being considered

The differential diagnosis includes 71-84% benign non-functioning adenomas, but also 1.2-12% adrenocortical carcinoma and 1.5-14% pheochromocytoma 1—making systematic evaluation essential to prevent missing life-threatening diagnoses while avoiding unnecessary surgery for benign lesions.

References

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